The aim of this program is to gain further insight into the underlying mechanisms of biological aging by investigating molecular alterations associated with specific age-dependent processes throughout the lifespan of the rat. A broad variety of research interests and experimental approaches will be focused upon the biochemical nature of those factors which regulate the chronological development, the adaptive capacity and, when applicable, the changes which accompany advancing age of a few, select physiological systems. The age-dependent processes included in this program are enzyme inducibility and general protein synthesis, characterization of hormone binding macromolecules, hormone production, myelination, histone metabolism, gluconeogenesis and lipogenesis. Major subthemes of the program include the role of receptor molecules in cellular responsiveness; fidelity of transcription and translation; and regulation of intermediary metabolism.